The vanity "value" to an amateur may be enough to just stroke his ego. A price is established by what a willing buyer and willing seller agree too. Unless there's duress, it's not theft or tantamount to theft. A photographer just has to say "no". If it's a one-of-a-kind photo, than it would be worth monetary value to the buyer. But if the buyer can get a similar photo for the cost of "vanity", than that's all the photo is worth, despite what you think it's worth.
This may sound cruel, but that's how it works. Better the photographer understand the market and adjust his game plan to create a photography niche that he could sell to and make money. Tilting windmills or shoveling s**t against the tide is no way for a businessman to operate.
I rather feat that you are getting a little too hung up on this whole amateur/professional divide. There is no sharp line or even foggy grey area in between, it's a graduation from one extreme to another nowadays and to try and operate on the basis that those who manage to make a living out of it are entitled to something that those who don't, are not, undermines any notion of value. Instead, all it does is confirm within the purchasers mind that they needn't pay for an image if it's taken by an amateur, and if that's the case why bother with pro's at all?
